When I was told that back pay and ssdi payments were not taxable, I assumed that meant I didn't have to pay the IRS. SSA does not withhold them unless otherwise instructed by you. I'm shaking I'm so mad. The government giveth then taketh away!! It took me over 7 years to finally win my benefits in 2010. Well, imagine how much backpay that was, plus, my monthly checks. Now I have to claim that as income along with my husbands pay. The backdate was 2005. We are seeking a good CPA to help us through this. The IRS is willing in these situations to accept monthly payments. With as much as I think we might have to pay, it could take me years to pay them back. Just a warning for those they didn't know this. If anybody has dealt with this same situation, any advice would really be appreciated.